This invention relates to a process for the production of Xanthomonas polysaccharide and particularly, to an improved fermentation medium for producing this polysaccharide by growing the bacterium Xanthomonas campestris.
The Xanthomonas polysaccharide has been developed mainly in the United States of America and used for industrial purposes such as an emulsion stabilizer, lubricants, latex and others.
A process for the production of Xanthomonas polysaccharide (hereinafter referred to as Xanthan gum) includes, in general, culturing the bacterium Xanthomonas campestris in a medium consisting of glucose or sucrose as a carbon source, distillers dried solubles or defatted soybeans as a protein source and minerals such as potassium phosphate and magnesium sulphate. Such a process is disclosed, for example, in U.S. Pat. No. 3,485,719.
On the other hand, a waste liquor which is obtained in the isolation of soybean proteins is known as a soybean whey. The soybean whey can be obtained, for example, by a process of extracting water soluble constituents from defatted soybeans with water, precipitating proteins at the isoelectric point (a pH of about 4.5) with acids and neutralizing the resulting supernatant liquid, by a process of washing defatted soybeans with an aqueous alcohol to remove beany flavor and distilling alcohol off therefrom, or as a waste liquor which is obtained by cooking soybeans in the boiling water. The soybean whey contains nutritious water soluble constituents, such as sucrose, raffinose, stachyose, water-soluble proteins, organic acids, vitamins, minerals and others.
Therefore the soybean whey has, hitherto, been employed in a concentrated form as a feed, or used as a culture medium for yeasts. Besides, it has been provided for recovering water-soluble proteins of good quality. Such utilizations, however, are unprofitable because the worths of the products obtained are low economically.